A study of the role of adipose tissue lipolysis and glycerol release in the control of gluconeogenesis will be undertaken in obese subjects before and after weight reduction and in non-obese volunteers during weight maintenance. The effect of carbohydrate intake and body weight will be studied in relation to the metabolism of adipose tissue, glycerol metabolism, serum lipolytic factors as well as plasma and muscle amino acids. A similar study will be conducted using normal and experimentally obese rats. The effects of jejuno-ileal shunting as a technique for the treatment of human obesity will be studied in terms of the mechanism of weight loss, effects on cholecytokinin levels and the behavioral consequences of weight reduction by this method.